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cc65/libsrc/common/isascii.s
2020-02-03 20:45:09 +01:00

25 lines
554 B
ArmAsm

; isascii.s
;
; This file is part of
; cc65 - a freeware C compiler for 6502 based systems
;
; https://cc65.github.io
;
; See "LICENSE" file for legal information.
;
; int isascii (int c);
;
.export _isascii
_isascii:
asl a ; high-bit to carry
txa ; check range of input param
bne @L1 ; out-of bounds?
adc #$FF ; calculate return value based on carry
rts
@L1: lda #$00 ; return false
tax
rts